What is zinc? Zinc is a metalic element. It is not found as an element. In Tennessee it is found as sphalerite - Zinc Sulfide (ZS)
When were they deposited? It was deposited from the Proterozoic through the middle Ordovician Periods.
| Quaternary |
| Tertiary |
| Cretaceous |
| Jurassic |
| Triassic |
| Permian |
| Pennsylvanian |
| Mississippian |
| Devonian |
| Silurian |
| Ordovician |
| Cambrian |
| Proterozoic |
- Brass is an alloy of copper and zinc. Brass is a shiny yellow metal that resists corrosion well - so it is useful for decorative metal objects and for hardware that will last outdoors.
- Coating iron with zinc - called galvanizing - protects the iron from rusting.
- Zinc oxide - a compound of zinc and oxygen - is a bright white material good for making pigments. It is used in some white paint.
- Zinc oxide is also used in skin creams that help healing. Since zinc oxide reflects sunlight, it is also used in some cosmetics that protect from sunburn.
- Pennies are made of zinc coated with bronze.
|
brass hook |
galvanized nail |
zinc core penny |
History of zinc mining in Tennessee Zinc productions began in east Tennessee, when an open pit mine started operation in Jefferson County in 1856.
Production grew slowly until after World War II. Then increased demand spurred exploration, which led to the discovery of the deposits in Smith County in the 1970's. After than prouction rose rapidly through the 1990's . (it fell briefly in the 1970's, when a major mine was closed.) Until 1990, Tennessee produced more zinc than any other state. As recently as 1992, the Division of Geology believed, "The future of the zinc industry in Tennessee is encouraging. Ore reserves appear to be adequate . . . and there is a market for nearly everything brought to the surface."
However, it is now cheaper to get zinc from mines elsewhere than from mines in Tennessee. In 1990 two huge mines opened in Alaska. In the early 1990's multinational corporations started buying Tennessee zinc mines, and by the second half of the 1990's these companies had started closing down the Tennessee mines becuase they no longer made money. As of 2004, there is no zinc mining in Tennessee.
How were they mined and processed? The first zinc mines in Tennessee were surface pits. Miners dug out the ore using hand tools. More recent discoveries are deep underground and are mined with heavy machinery.
Zinc is found mixed with rock. To separate it, the zinc ore is ground into a fine powder. Then this powder is mixed with a heavy liquid. Zinc is heavier than the rock with which it is found, so the zinc sinks in the liquid and the rock floats. This lets the mining machinery separate the zinc from the rock.
The most common ore of zinc in Tennessee is sphalerite (ZnS - zinc sulfide). This is generally found along with galena (PbS - lead sulfide). Although zinc itself is not considered toxic, both lead and sulfur are serious pollutants. Lead is a "heavy metal" and is extremely poisonous. Sulfur is a major source of acid in the water supply. Abandoned mines can fill with water, polluting streams and groundwater downstream from the mines.